摘要:

The article gives a systematic account of the results of experimental and theoretical studies of ion components produced in the sputtering of pure metals. Experimental dependences of the characteristics of this phenomenon on a number of parameters are analyzed on the basis of criteria proposed for the purity of the experimental condition and, in particular, for the chemical cleanness. Existing theories of the phenomenon are classified, discussed and critically analyzed. Special attention is paid to the experimental discrimination of specific theoretical models.

ISSN:0033-7579    

DOI:10.1080/00337578008209996

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Angle Resolved ion-Electron Spectroscopy (ARIES), combined with Low Energy Ion Scattering (LEIS), is presented as a new technique with a wide applicability to study solid surfaces. Energy and angular distribution of secondary electrons emitted due to the ionization of (ad)-sorbates on a Cu (001) surface upon bombardment with 10 keV He+are examined. When sulphur atoms—diffused from the bulk to the surface upon a 600°C anneal—are involved in the emission process, a strongly anisotropical emission is found. The anisotropy is related only to the incoming beam direction and appears to be fully independent of the copper target orientation. Some points of importance for a theoretical description are discussed. The anisotropy effect can effectively be used to determine the relative position of contaminant and substrate atoms in the uppermost surface layers. Thus, it is found that (1) sulphur atoms diffused to positions just below the surface occupy substitutional sites and (2)in this situation surface relaxation for the copper atoms in the first layer is negligible.

ISSN:0033-7579    

DOI:10.1080/00337578008209997

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The channeling Rutherford back scattering technique (RBS) has been used to investigate pulsedQ-switched ruby laser and CW Nd-YAG laser annealing of ⟨111⟩ Si single crystals implanted with 40-keV Bi to a dose of 1 × 1014/cm2. The pulsed laser annealing completely removed implantation induced lattice damage and left high impurity substitutionality. However, redistribution of Bi atoms occurred in the annealing process; the percentage of impurities, which segregated at the surface reached 30% and 60% for a single pulse and overlapped pulse, respectively. This implies that a surface melting process occurred. The same sample was also annealed by a CW Nd-YAG laser. Backscattering spectra indicated that recrystallization occurred by means of a thermal solid-phase epitaxial regrowth process, which under appropriate conditions optimized almost completely the recovery of the lattice damage, leaving the Bi atoms mainly in substitutional sites (∼90%) without impurity redistribution.

ISSN:0033-7579    

DOI:10.1080/00337578008209998

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The effects of local excitation density and of applied electric field on the luminescence spectra of CdS and CuCl induced by bombardments with MeV H+or He+have been studied. It is found that the intensity of theMline (4870 Å) relative to that of thePline (4906 Å) in CdS increases as the local excitation density increases and the intensity of theMline is reduced by applied electric field. The ratio of the intensity of theMT(3911 Å) andML(3918 Å) lines to that of theXline (3926 Å) in CuCl is found to be almost insensitive to the local excitation density and the intensities of each line are insensitive to applied electric field. TheXline is also found to be less sensitive to the radiation induced defects than theMTandMLlines. Theoretical calculation of the thermalization of the electrons and holes in an ion track is also made, showing that the density of electrons and holes in ion tracks is sufficiently high for the electron-hole plasma to be created. It is suggested that theMline in CdS and theXline in CuCl is due to the electron-hole plasma. With this assignment the dependence of the intensity of each luminescence line on the excitation density and on the applied electric field and their line shapes are explained.

ISSN:0033-7579    

DOI:10.1080/00337578008209999

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A void interaction mechanism based on the diffusion exchange of point defects is studied for a system of N-voids. In the absence of additional sinks for point defects, an expression is derived for the growth rate of a void, taking into account the influence of the other voids on its growth. It is shown that the average size of the interacting voids is constant while the dispersion of void size distribution increases with the characteristic time close to the growth rate of noninteracting voids at the coalescence state. This quantity determines the incubation time of the lattice under annealing.

ISSN:0033-7579    

DOI:10.1080/00337578008210000

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The dependence of the average electron energy losses of protons with Eo ⋍ 6 MeV channeled in the {110} planar channel of a tungsten crystal upon the dechanneling depth has been investigated using the Hartree-Foch approximation for the core electrons and the free electron model of Lindhard for the valence electrons. The calculated results agree qualitatively with the experimental data available. It has been shown that the approximation of the average excitation energies of atomic electrons is not enough to reach a quantitative agreement with experiment and that one should correctly take into account the core-electron excitations caused by the transmitted particles, including those moving near the centre of a channel. It has also been demonstrated that the experimental dependence of the average channeled particle energy losses on the dechanneling depth offers additional possibilities for checking and refining the existing theoretical models of charged particle stopping in solids.

ISSN:0033-7579    

DOI:10.1080/00337578008210001

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A method is described for calculating approximate electron ranges. The method uses a simple but less accurate analytic expression for electron range derived in calculations of cascade showers. An energy dependent correction factor is then applied to give reasonable agreement with calculations using the more rigorous theoretical treatment employing the continuous slowing down approximation. It is shown that, if energy dependent correction factors are derived for one element (e.g. aluminium), then these same correction factors can be used to compute electron ranges in other materials that are not too different in atomic weight.

ISSN:0033-7579    

DOI:10.1080/00337578008210002

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A detailed study has been made by infrared spectroscopy (IR) techniques of the near-edge absorption and distinct absorption bands introduced in high purity float zone (FZ) silicon containing ≤1016interstitial oxygen (Oi)cm−3and in high purity Czochralski (Cz)grown silicon containing 2.4 × Oicm−3in the 1–50μm wavelength region after ≤ 100°C fast (≥ 1 MeV) neutron irradiation and during 20 min isochronal annealing at 50°C steps from 150 to 900°C. The relationship between absorption due to near-edge, divacancy, single-phonon, and higher-order band formation was investigated as a function of Oicontent, fast neutron fluence, and different lattice defect-impurity interaction. Seven distinct new absorption bands were observed in the 9.5–12.1 μm region in the Cz silicon samples only after irradiation and partial annealing. These bands may correspond to different vacancy-oxygen defect structures previously identified by electron paramagnetic resonance (EPR) techniques. Almost complete ŕemoval of all IR-active defect centers was observed in all FZ or Cz silicon samples after annealing for 20 min at 750°C, when electrical property measurements on companion samples indicated the anticipated carrier concentration and mobility due to transmutation-introduced phosphorus.

ISSN:0033-7579    

DOI:10.1080/00337578008210003

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

We have studied the sputtering of235U from UF4surfaces by ions with energies in the electronic stopping region. The observed sputtering yields are very large and are associated with the electronic stopping power. Measured yields produced by19F ions at energies ranging from 1/16 MeV/amu to 1½ Mev/amu exhibit a peak ofS= 7.1 ± 1.5 for19F+3at an energy of ¼ MeV/amu. The data suggest that the yield depends on the charge state of the incident ion. The yields are independent of target temperature in the range between 70°C and 170°C. The energy spectrum of the neutral component of the sputtered particles produced by ¼ MeV/amu19F+2has been measured with the mechanical time-of-flight spectrometer developed by Weller and Tombrello. The spectrometer data indicate that a large fraction of the sputtered particles is charged. We also describe the behavior of high energy sputtering of UF4by4He,16O and20Ne. Experiments with16O and20Ne beams at 100 keV show that the Sigmund theory adequately describes the sputtering of UF4in the nuclear stopping region.

ISSN:0033-7579    

DOI:10.1080/00337578008210004

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Annealed polycrystalline copper samples are implanted with 325 keV H+-ions at ambient temperature for total fluences of 2.2–8.4 × 1018ions/cm2, and are examined using SEM and optical microscope. The critical fluence for blistering is about 5.2 × 1018ions/cm2. The observations reported are (i) preferential decoration of grain boundaries with elongated blisters which have a tendency of interconnecting each other, (ii) irradiation induced grain boundary movement, (iii) onset of blistering only on few grains and tendency of coalescence, at the critical dose, (iv) spongy blister skins, and (v) simultaneous occurrence of blister exfoliation from the top and from the periphery. The observation (i) is attributed to preferential nucleation of gas bubbles along the grain boundaries and their successive coalescence; (ii) and (iii) are assigned to partial channelling; (iv) is understood to be a consequence of the growth and the coalescence of the bubbles within the skin: and (v) is considered to be the beam power effect. The D-t relationship predicted by the stress model is also examined. The measured skin thickness is within 18% of the calculated projected range.

ISSN:0033-7579    

DOI:10.1080/00337578008210005

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor